1. Field of the Invention
The present invention relates to a powder container for collecting and accumulating powder such as waste toner, and an image forming apparatus including the powder container.
2. Description of the Related Art
In image forming apparatuses such as a copier, toner that has not been transferred and remains on a photosensitive drum or an intermediate transfer belt that transfers a toner image to a recording medium or intermediate transfer body is eliminated by a cleaning mechanism, collected, and accumulated in a powder collecting box.
The powder collecting box includes a toner entrance connected to the cleaning mechanism, a toner conveyor that transports toner charged in the box, and a toner detector that detects the degree of storage (filling rate) of the toner in the box. When it is detected by the toner detector that the box is full of toner, the powder collecting box is replaced.
To enhance user's convenience, the number of replacing the powder collecting box is desirably as small as possible and the capacity of the box is thus as large as possible. As is commonly known, in the image forming apparatuses, compactness and cost reduction have progressed. Actually, the box cannot be enlarged only to improve the powder collecting capability.
The powder collecting box is usually placed in a so-called dead space such as between a feeding unit placed at the bottom of the image forming apparatus main body and an image forming unit placed above the feeding unit.
If there is not much room for the image forming apparatus main body in the height direction because of its compactness, the powder collecting box needs to be made to be extend in the longitudinal and transverse directions (X and Y directions) and reduced in the height direction (Z direction). The powder collecting box thus tends to be made in a flat box shape that extends in the horizontal direction and has a low height.
It is significantly difficult to accumulate toner uniformly in the flat box. The toner can be accumulated in a partially solidified state. If the solidified toner is accumulated near the toner detector, the full state of the box is detected despite the box is not full. The box that does not reach its full state is required to be replaced earlier, resulting in a decrease in user's convenience.
A conveyor that transports and equalizes toner needs to be provided in the powder collecting box and toner cartridges having such conveyor are disclosed (see, for example, Japanese Patent Application Laid-open No. H11-2947). In the toner cartridge disclosed in Japanese Patent Application Laid-open No. H11-2947, an eccentric cam is provided at the shaft of a screw for supplying toner externally, a plate is reciprocated by the eccentric cam in the horizontal direction, and toner is conveyed by internally directed protrusions with truncated V-shaped configurations that are integrally formed at the plate. The cartridge is provided to supply toner efficiently to the last while preventing aggregation of the accumulated toner. While the conveying directions of the protrusions that are placed in the truncated V-shaped configuration and serve as conveying members are crossing with each other and different as shown in FIG. 7 of the above patent document, the toner is unidirectionally directed to the toner detector by the interaction of the protrusions. A unit that detects the remaining amount of toner is provided in the cartridge.
However, flow and pulsation of the accumulated toner are generated by the internal conveyor in the toner cartridge with the above configuration. The sensor that detects the amount of toner can be also affected thereby, and detection accuracy is significantly decreased.